Gliederung

Objective

The purpose of this study was to analyze the levels of neurotrophic factors in the CSF of patients with chronic neuropathic pain in comparison to controls with lumbar back disorders and hydrocephalus. The pathophysiology of neuropathic pain is still poorly understood. Studies in experimental animals showed that neurotrophic factors such as GDNF, BDNF, CNTF and βNGF might be involved in the processing of neuropathic pain at spinal relays in the dorsal root entry zone. Thus far, it has not been investigated whether neurotrophic factors are altered in the cerebrospinal fluid (CSF) of patients with different pain syndromes.

Methods

The levels of GDNF, BDNF, CNTF, and β-NGF were analyzed in the lumbar CSF of 8 patients with chronic neuropathic pain, 10 patients with normal pressure hydrocephalus (NPH) and 20 patients with lumbar back disorders undergoing myelography, by using ELISA assays. The myelographies were performed for diagnostic purposes, and in the NPH patients CSF was removed to select patients for surgery. The protocol was approved by the local Ethics Committee, and all patients gave informed consent.

Results

The CSF titers of BDNF, CNTF and β-NGF were not significantly different in patients with neuropathic pain when compared to patients with lumbar back disorders, or to patients with NPH. Preleminary results showed that the concentrations of GDNF in patients with neuropathic pain were found to be significantly lower as compared to the group of patients with lumbar back disorders (P<0.05), but were not significantly different from the group of patients with NPH.

Conclusions

These findings may indicate a role of GDNF in the pathophysiology of neuropathic pain. Further investigations are necessary to confirm this observation, and to clarify the possible role between the turnover of GDNF and the development of neuropathic pain in man.